Thresher concave with rubber threshing bars



- E. J. JOHNSON THRESHER CONCAVE WITH RUBBER THRESHING BARS Dec. 28, 1948 vFiled Jan. 5, 1945 OOOODOOOO OOOGQOOOOOO 2O 22 I I5 IIII FIGA

ERIC J. JOH NSON w1 TN@ 5J. c 'fmt Patented Dec. 28, 1948 THRESHER CONCAV WITH `RUBBER THRESHING BARSv Eric J. Johnson, Moline, Illa, assignor to Deere & Company, Moline, Ill., a corporation of `Illinois Application January 5, 1945, Serial No.v 571,706

' 'The present invention relates generally to threshing apparatus and has for its principal.

object the provision of a novel and improved concave of greater eciency and otherwise better operation.

' More specifically it is an object oi my invention to provide a threshing concave which is partieularly well adapted forvuse in threshing rice, butwhich can also be used for other grains. As isfwell known tov those skilled in the art, rice is more diflcult to thresh than many other crops for the reason that,`when threshing with conventional mechanism, many of the kernels may be cracked or broken if the threshing mechanism is sufficiently aggressive to thresh the entire crop without loss. Therefore, it is a further speciiic object oi my invention to provide a rice concave which is sufficiently aggressive to thresh the entire crop without appreciable loss, but with,-Y out cracking or otherwise damaging the kernels of rice.

These and other objects and advantages of my invention will be apparent to those skilled in the 'art after a consideration of the following description, in which reference is had to the drawings appended hereto, in which Figure 1 is` a plan View of a thresher concave embodying the principles of my invention, and Figure 2 is a sectional lelevational View taken longitudinally through a threshing device including a cylinder and concave.

Referring now to the drawings, the concave is indicated in its entirety by the reference numeral t and comprises a supporting frame l including a plurality of laterally spaced concavely curved longitudinally extending frame bars 'l and a plu' rality oi longitudinally spaced transversely extending frame bars 8 rigidly fixed thereto to form a grid. The grid 6 is curved in an arc about the axis of rotation of a threshing cylinder Iii, which is rotatably mounted on a shaft ii above the concave 5. The frame bars l, 8 are rigidly interconnected, as by welding, to form the grid 6.'

Supported on the frame or lgrid is a curved sheet metal pan or trough l2, which is also curved in an arc substantially about the axis oi the cylinder shaft II and is provided with a series of longitudinally spaced transversely extending'grooves vor depressions I3, which are formed 8 Claims. (01.130-27) 2 rearward wall I5 of each groove is inclined from the apex rearwardly and upwardly.

The-threshing element on the concave 6 is indicated by the reference numeral 20, each of which comprises a flat rubber bar or strip which extends transversely from one end of the concave to the other and lies flat against the upwardlyand rearwardly inclined wall I5 of each groove I3. The width of each rubber bar 20 is greater than the width of the associated wall I5, so that with one edge of the rubberv bar at the vertex or bottom of the groove I3, the bar extends outwardly beyond the upper edge of the wall I5 or, in othergwords, beyond the curved surface of the sheet metal pan I2, and is unsupported at lits upper or rearward edge. The thickness ci the rubber bar is suiicient so that the upper unsupported edge does not sag of its own weight, but" the thickness is appreciably less than the width of thev rubber bar 2D. rubber bars 26 are secured to the inclined walls l5 by means of laterally spaced bolts 2l, which are inserted through aligned openings inthe wall I5, the rubbei` strip 2li, and through a metal strip22 and are rigidly secured by nuts 23 threaded on the lower ends of thebolts ZI beneath the wall I5,`thus the heads of thel bolts 2| are disposed down in the grooves I3, and the metal strips 22 serve to prevent the heads of the bolts 2I from imbeddng into the rubber. 22 if desired could be replaced by any other suitable means, such as washers, for increasing the area of the bearing surface, as is well known to those skilled in the art.

Mounting flanges 25 are provided along the outer sides of the two outer longitudinal frame bars 'l and these fianges are providedwith apertures or slots 2d which are adapted to receive bolts for securing the concave ii in a body of a thresher or combine (not shown). The front transverse `member 8 is provided with a iorwardly extending upper flange 2S, to which is secured a metal apron 21 by suitable bolts 2%.

' During operation, the harvested grain is fed.

to the threshing mechanism by means of a conveyor indicated at 3l), which delivers the crop over the apron 2l to the concave. The cylinder iii rotates in the direction shown by the arrow andlis provided with transversely disposed conventional thresher bars v3I preferably of the rasp bar type, which rub the grain against the rubber bars `.'Z'to separate the kernels from the stalks. The upper surface of eachoi the rubber concave bars 20 is corrugated, as indicated at 32, against which the straw is rubber, and the friction of the The- The strips straw against the rubber bars retards the straw considerably, thereby pemitting the rasp bars t0 strip the kernels of rice or other grain from the stalks. The yielding resilient characteristics of the rubber bars prevent the kernels of grain from being cracked or broken.

The downwardly and rearwardly inclined walls I4 of the grooveslf'3" are provided witha plurality of perforations 33, which permit thev threshed kernels of grain to drop through the concave to the grain pan or other device (not shown) which'.

is provided in the conventionalthresher for receiving the grain.

It will be noted that in the embodiment shown and described herein, there1are?fourrrubben'confcave bars 20, although a lesser number caniv beusedif so desired. Preferably, each of the rubber bars is disposed in a plane which intersects the plane tangent to the periphery of theicylinder at an acute angle A', which is the same for alLcf the four rubber` bars. bars are inclined rearwardly at an acute angle to planes which pass through. the axis of curvature of the concave and intersect the respective bars, as: indicated at B and the corresponding angles foreach` ofi the four barsfare Vequal.

After thekernelshave been threshed from the straw, the latter is discharged upwardly and rearwardly over a downwardly curved metal sheet 35 whichy is` secured along. the rear edge of the concave-pan or. trough.

I claim;

1. In a thresher, a concave comprising a curved perforated sheet metal pan creased inwardly to provide a zigzag cross section defining transverse grooves in the concave side thereof, a rubber bar disposed in each groove and projecting outwardly therefrom in unsupported relation toward the center of curvature, and means disposed within 'said' grooves below the topsthereof for securing said bars-therein.

2. In a thresher, a concave comprising a curved pan having transverse grooves of V-shaped cross section, a rubberr bar disposed in each groove against the rear side of the latter inclined in the direction of movement of the threshing cylinder and having an outer edge projected outwardly of said groove in unsupported relation, and means securing said bars in said concave.

3. Ina thresher, a concave comprising a curved pan having transverse grooves, eachgroove being defined by a downwardly and rearwardly inclined-wall-andv an upwardly and rearwardly in clined wall, nat rubber bars lying against said upwardly and rearwardly inclined walls, re-

spectively, and` having rear edges projecting in unsupportedv relation beyond the upper edges of the latter walls, and means in said grooves for securing said bars therein.

4. In a thresher, a concave comprising a curved steet metal pan having transverse grooves de.- pressed therein, each groove being defined. by a downwardly and rearwardly inclined wall, the latter being perforated to permit. passage of threshed. grain therethrough, and an upwardly and rearwardly inclined wall, at rubber bars lying against said last mentioned walls, respectively, and having rear edges projecting upwardly beyond the upper edges of theassociated walls. in unsupported relation, and means for. securing` said: bars to said upwardly and rearwardlyin clined walls.

5; In. a thresher, a'. concave. comprising a framev The i'iat sides of theincluding a plurality of laterally spaced concavely curved longitudinally extending frame bars and a plurality of longitudinally spaced transversely extending frame bars rigidly xed thereto to form a grid, a sheet metal concave pan secured to said grid and having transverse grooves depressed therein between said transverse framefbars, each.grooveibeingidenedby a downwardly and` rearwardly inclined. wall. and an upwardly and rearwardly inclined wall, at rubber bars lying against said last mentioned walls, respectively, and securing bolts extending through aligned openings in said bars and said upwardly and rearwardly inclined walls for securing, said bars thereto.

6.. In athresher,.a concave comprising a frame including a plurality of laterally spaced concavely curved longitudinally extending frame bars and a plurality of longitudinally spaced transversely extending frame bars rigidly iixed thereto to forni a grid, a sheet metal concave pan secured to said grid and` having transverse grooves' de.- pressed therein between said transverse frame bars, each groove being dened by a downwardly and rearwardly inclined wall' and an upwardly and rearwardly inclined wall, flat. rubberbars lying against said last mentioned walls; respec.- tively, and having rear edges projecting upwardly.' beyond the upper edges of the associated wallsin. unsupported relation, and bolts extending through aligned openings in said upwardly and rearwardly inclined. walls and in the lower. portions of'said flat rubber bars, respectively," for securing the latter.

'7. In a thresher, a concave comprising/a' framei curved concavely, a plurality of longitudinallyY spaced, transverse rubber bars having' a width appreciably greater than the thickness thereof, and. means for securing said bars in supported relation on said concave frame with the flat sides of the bars inclined rearwardly at acute angles'- to planes in which lie the transverse axis of cur-f vature of said concave and intersecting the respective bars, said securing means engaging the' lower portions of said bars, With the upper: rear edges of said bars projecting upwardly beyonds said frame in unsupported relation.

8. In a thresher, a concave frame and means dening' a bar-supporting surface extendingv axially of said concave frame and inclined inthe' direction of movement or grain at an acute angle' to a plane in which lies the axis of curvature of the concave andwhich intersects said surface, and a flatrubber threshing bar having a width'- appreciably greater than its thickness and disposed with its flat side against said inclined sur'- face, but withthe inner edge projecting upwardlyl beyond said bar-supporting surface in unsup' ported relation, and bolt means securing the lower edge of said bar to'said concave.

ERIC J. JO-HNSGN-l REFERENCES CITED The following references are ofv recordin the. iile of this patent:

UNITED STATES PATENTS' Number Name Datel 295,305 Swingle Mar. 181884 2,227,225 Lackey Dec. 311940. 2,262,453 Dray Nov. 11" 1941. 2,305,964 Harrison Dec'. 22; 1942 2,349,380 Rietz May 23,' 1944" 

